The present disclosure relates to medical devices, systems, and methods. In particular, the present disclosure relates to the percutaneous delivery and deployment of a temporary aortic valve to facilitate other percutaneous procedures such as the delivery of aortic replacement valves or to serve as a standalone hemodynamic support device when the native aortic valve is damaged from infective endocarditis or trauma, for example. The native aortic valve damage may also be iatrogenic from deliberate valve resection prior to valve placement.
The native aortic valve can fail acutely from infection or mechanical trauma. In endocarditis of the aortic valve, the timing for surgery may be limited during the active phase of the infection. The condition can be fatal as significant acute aortic regurgitation may cause decompensating heart failure. Mechanical failure of the aortic valve can occur from proximal aortic dissection or direct leaflet and/or annular tear with similar potential lethal outcome. Patients suffering from significant aortic valve disease are frequently treated by aortic valve replacement procedures. While most aortic valve replacements are still performed in open chest procedures, recently there have been significant advances in minimally invasive aortic valve replacement where the valve is introduced through a transapical approach (minimally invasive), a transaortic approach (minimally invasive), or a transvascular (percutaneous) approach over the aortic arch. In the era of transcatheter aortic valve intervention (TAVI), iatrogenic damage to the aortic valve may become relevant especially with suggestions for valve resection prior to replacement. The clinical needs for a percutaneous temporary aortic valve are therefore apparent.
Transapical, transaortic, and transfemoral percutaneous aortic valve procedures are “beating heart” procedures where continuing blood flow from the left ventricle into the aorta creates hemodynamic forces on the replacement valves and the tools used in the replacement procedures. In an effort to control the hemodynamic forces and to stabilize the tools and valve used for replacement, that the use of a “temporary aortic valve” (TAV) has recently been proposed. As described in commonly owned published U.S. Patent Publications Nos. US 2009/0030503, US 2009/0030510 and US 2012/0116439, the full disclosures of which are incorporated herein by reference, a catheter is intravascularly introduced over the aortic arch to position a balloon assembly in the ascending aorta just above the Sinus of Valsalva. The balloon assembly includes three equally sized balloons disposed in parallel about the distal tip of the catheter, and the inflated balloons together limit retrograde blood flow (flow in the direction from the aorta toward the aortic valve) during diastole, thus limiting disturbance of the tools and/or valves located in the aortic valve annulus during the procedure. The balloon inflation only partially occludes the aortic lumen in order to both allow antegrade flow during systole and to permit a limited retrograde flow during diastole in order to perfuse the coronary vasculature through the Sinus of Valsalva and to protect the left ventricle from excessive volume overload. As a standalone procedure, in cases of naturally occurring damage (as opposed to iatrogenic) of the native aortic valve such as from infective endocarditis or trauma, the temporary aortic valve can also be placed similarly in the ascending aorta as a hemodynamic support device.
While of great potential benefit, the use of the fixed-balloon structures described in the prior patent applications is necessarily a compromise between resistance to regurgitation during diastole and forward blood flow patency through the aorta during systole. Even when the balloons are collapsed to their minimum cross-sectional area in a counter-pulsating balloon system, the complex balloon structures may be cumbersome to advance through tortuous vasculature and may be prone to mechanical failure, particularly due to the relatively high number of mechanical elements and after repeated cycles of expansion and collapse.
Previous models of catheter-based temporary aortic valves for the treatment of acute aortic regurgitation have also not reached clinical relevance mostly due to their inability to adequately protect coronary circulation. When deployed in the ascending aorta, the compromised diastolic coronary flow from acute aortic regurgitation has been shown to further reduce from the occlusive nature of the device designs. Myocardial ischemia can occur in acute aortic regurgitation alone without concomitant coronary artery disease. Coronary flow obstruction by the temporary aortic valve should therefore be overcome in improved device designs.
For these reasons, it would be desirable to provide improved methods and systems for occluding the aorta to limit aortic regurgitation during valve repair and replacement procedures as well as to provide a standalone device for hemodynamic support in the native aortic valve when damaged by naturally occurring aortic regurgitation, such as from infective endocarditis or trauma. In at least the latter application, the methods and systems can be a life-saving bridge to open heart surgery to correct the aortic valve damage.
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